Cognitive changes in older adults following intensive care unit stays

Clinical question

How can we help older adults who have cognitive changes after intensive care unit (ICU) stays?

Bottom line

Post–intensive care syndrome (PICS) encompasses new or worsening cognitive or physical impairments following admission to an ICU that persist beyond hospitalization for acute care.¹ Anticipated increases in PICS prevalence owing to the aging population in Canada have important implications for ICU patients, their families, and the Canadian health care system. Greater prevalence of PICS also has implications for family physicians, as they manage most posthospital care for individuals who survive stays in ICUs. This paper summarizes key points from an article published in the Canadian Geriatrics Society Journal of CME.²

Evidence

• Post–intensive care syndrome cognitive impairment is common, with mean prevalence ranging from 35% to 81% at 3 months after ICU discharge (based on subjective and objective cognitive assessments, respectively).³

• Risk factors include pre-existing cognitive impairment, delirium, longer duration of delirium, presence of sepsis, acute respiratory distress syndrome, and shock.^4,5

• Society of Critical Care Medicine recommendations call for screening ICU survivors for PICS within 2 to 4 weeks of hospital discharge and for conducting serial assessments thereafter.⁶

• Forty-six percent of ICU survivors have persistent cognitive impairment 24 months after discharge.³

Approach

It is important to recognize cognitive impairment in ICU survivors; early recognition, management, and counselling may improve understanding of disease trajectory for patients and their families, enhance function, and optimize support.⁷ Management is summarized in Table 1.^1,7-15

Table 1.

Management of PICS cognitive impairment

GOAL	ACTION	EXPLANATION
Improve cognition	Treat underlying confounding factors	This includes medication review; management of underlying anxiety, depression, or PTSD; screening blood work; neuroimaging; and referral for sleep study if obstructive sleep apnea is suspected
	Refer to cognitive rehabilitation program	Cognitive rehabilitation for younger ICU survivors without pre-existing cognitive impairment is associated with improvement in executive function, memory, and attention.7,8 Cognitive rehabilitation for older ICU survivors should be considered if available, but this has not been studied directly
		In the absence of formal cognitive rehabilitation, referral to an occupational therapist may be considered for reviewing self-efficacy and goal management
	Refer to physical rehabilitation program and recommend daily exercise	In addition to other physical and mental health benefits, there are cognitive benefits to staying physically active, and exercise should be encouraged. Among ICU survivors, early physical therapy has demonstrated benefit for improved physical function and mortality.8 Referral to an exercise program for older adults may help increase adherence and provide socialization
Stabilize cognition	Recommend reducing or eliminating alcohol intake	Limiting alcohol intake (or abstaining, preferably) is suggested
	Advise patient to maintain adequate sleep	Impaired sleep following ICU admission is common. Nonpharmacologic strategies such as sleep hygiene and cognitive behavioural therapy for insomnia should be used. Sleepwell, a not-for-profit initiative, has published patient resources curated by researchers at Dalhousie University in Halifax, NS9
		Practical advice related to assessment and management of insomnia in elderly patients has been published to guide care10,11
		Should medication be sought, we suggest 3 mg of melatonin taken orally in the early evening
	Recommend environmental modification	Request an occupational therapy home safety assessment
		Home adjustments may include large clocks, calendars, and planners that are visible and accessible as well as bright lighting over work areas such as those in the kitchen and bathroom. The Centers for Disease Control and Prevention has published a checklist to help older adults reduce the risk of falling12
	Recommend peer support counselling	Support groups for ICU survivors are good sources of counselling, community, and practical advice and education.13 Patient and family resources are also available from the Society of Critical Care Medicine14
Prevent worsening	Discuss goals of care	During reassessments, patient perspectives on their ICU experience, post-ICU course, and preferences regarding future ICU care should be addressed
		Specifically, if patients have experienced cognitive impairment following ICU admission and have not improved to their pre-ICU baseline despite appropriate time and management, they and their caregivers should be prepared for the possibility that future ICU admissions may result in further cognitive decline
	Manage modifiable risk factors for dementia	Managing modifiable risk factors for dementia can help protect against further decline in cognition from a secondary neurodegenerative cause. As always, management should consider time to benefit of proposed treatment in the context of the individual’s life expectancy and goals of care. This includes the following: Managing hypertension, diabetes, obesity, and smoking cessation Addressing social isolation: refer to local community resources Addressing hearing impairment: refer to audiology if patient or caregivers have concerns
	Screen for safety concerns	Cognitive changes can result in safety concerns for the patient and others. These include the following: Driving: assess driving safety and formal reporting of driving concerns as per jurisdiction requirements Wandering and physical aggression: consider referral to geriatric medicine or geriatric psychiatry if behavioural and psychological symptoms of dementia are present Home safety: burning kitchenware or having incidents with fires or floods in the home may indicate the patient requires a higher level of supervision, either in their own home or in an alternative environment (eg, assisted living, retirement home, long-term care) Financial safety: ensure a power of attorney for finances and personal care is in place Suicidal thoughts: survivors of critical illness treated in ICUs have increased risks of suicide (AHR=1.22, 95% CI 1.11-1.33) and self-harm (AHR=1.15, 95% CI 1.12-1.19)15
Address caregivers’ needs	Discuss family support	Family members of ICU survivors may experience physical and mental impairments following the patient’s ICU experience, termed PICS family. Symptoms may include interrupted sleep, anxiety, depression, grief, and PTSD.1 Given the impact that social circles have on health and well-being, it is important to consider whether the needs of your patient’s caregivers are also addressed. Family resources are available from the Society of Critical Care Medicine14

AHR—adjusted hazard ratio, ICU—intensive care unit, PICS—post-intensive care syndrome, PTSD—posttraumatic stress disorder.

A practical set of criteria for PICS cognitive impairment should include

• new (not present prior to ICU admission) or worsening subjective cognitive changes reported as part of the history by the patient or by a reliable informant;

• objective deficits on cognitive testing;

• presence of functional impact; and

• no identified reversible causes or factors.

Implementation

History. Deficits seen in patients with PICS cognitive impairment include executive function (planning and sequencing tasks), short-term memory, attention or concentration, and mental processing speed.¹⁶

The impact of cognitive changes on a patient’s day-to-day life may be difficult to assess in ICU survivors, as they may also have PICS-related physical impairment causing limitations in basic or instrumental activities of daily living. To explore cognitive effects on function, ask questions such as, “Are there things you (or the person you are caring for) are no longer able to do because of the way you (they) think? For example, playing cards, completing crossword puzzles, or participating in another hobby?”

Objective testing. We suggest screening for cognitive impairment by evaluating commonly affected domains as part of a comprehensive assessment that includes patient and caregiver reports of cognitive changes related to ICU admission. Various cognitive testing options exist that can be selected based on your practice situation and patients’ needs.¹⁷

Confounding causes. Rule out other potential factors in cognitive impairment. Consider effects of new medications—including benzodiazepines, antipsychotics, opioids, or anticholinergics—started in hospital. Mood disorders may present with cognitive changes. Obstructive sleep apnea is missed easily and may impair executive function, which overlaps with the presentation of PICS cognitive impairment.

Basic laboratory test screening may be considered. If brain imaging has not been done since discharge from the ICU, it is reasonable to obtain a noncontrast computed tomography or magnetic resonance imaging scan, if available. Neuroimaging helps assess for causes of cognitive changes such as ischemia and may help with prognosis by showing patterns of atrophy suggestive of primary neuro-cognitive disorders such as Alzheimer disease.

Patients admitted to ICUs with diagnoses of traumatic brain injury or stroke are typically excluded from studies of PICS cognitive impairment. Pre-existing dementia, however, is not an exclusion criterion and patients with pre-existing dementia who experience declines in cognition after ICU admission should be considered as having PICS cognitive impairment.

Prognosis. It is hypothesized that prognosis variability relates to the underlying critical illness, such as septic shock, acute respiratory distress syndrome, or trauma.³ Factors such as delirium or unmasking of dementia may affect individual prognoses in older adults. Pragmatically, prognoses can be divided into the following:

Improvement, if PICS cognitive impairment is primarily due to resolving delirium: Symptoms of delirium can persist 6 months or longer after hospital discharge in older adults not admitted to ICU, but most improve over time.¹⁸ Given that the prevalence of delirium among ICU patients may be as high as 80%, patients presenting with PICS cognitive impairment may have similar potential to improve in the months following ICU discharge.¹⁸

Stability, if PICS cognitive impairment is primarily due to acquired brain injury (ABI): If the patient’s PICS cognitive impairment is primarily attributable to ABI from hypoxia, hypotension, glucose dysregulation, or inflammatory and cytokine response during critical illness, deficits may be more persistent but are not expected to worsen if no new insult is experienced. With rehabilitation such patients may improve, as with other populations of patients with ABI.^7,16

Progression, if PICS cognitive impairment is primarily due to a pre-existing or unmasked neurodegenerative disorder: Cognitively intact older adults may be found to have neuropathologic changes of Alzheimer disease on autopsy without having had clinical symptoms.¹⁹ Features of dementia can appear when additional stressors on the brain, such as delirium or ischemic events, overcome an individual’s cognitive reserve. In these circumstances, cognitive decline may progress over time in keeping with dementia syndromes.

Serial assessments at 3, 6, and 12 months after hospital discharge may clarify a patient’s cognitive trajectory, which may help with counselling related to prognosis.⁶ Referral to geriatric medicine or geriatric psychiatry may be considered, depending on circumstances and availability.

There are currently no pharmacologic options for management of PICS cognitive impairment; nonpharmacologic management is the mainstay of treatment. Individualized treatment plans should be created through shared decision making between the clinician, patient, and caregivers.

Geriatric Gems are produced in association with the Canadian Geriatrics Society Journal of CME, a free peer-reviewed journal published by the Canadian Geriatrics Society (http://www.geriatricsjournal.ca). The articles summarize evidence from review articles published in the Canadian Geriatrics Society Journal of CME and offer practical approaches for family physicians caring for elderly patients.